The adipose of edible meat consists of fat matrixed in membraned cells in such a way that it is not simply free fat but a natural composition exhibiting specific characteristics of its own. Chicken skin, the white portions of bacon, milk fat globules, and suet are good, representative examples.
In comminuted meat, such as hamburger and ground sausage, adipose is distributed throughout as a separate, distinct component of the meat. The association of adipose lipid and adipose tissue results in specific and distinct complexes which do not behave as lipids do by themselves. For example, hamburger and sausage adipose contains a great deal of the ultimate aroma and taste characteristics of prepared hamburger and sausage. And, it does not melt all at once like the lipid alone would do. When the meat is cooked, the lipid portion of its adipose tissue can be dissociated from the remaining, primarily proteinaceous parts only with difficulty and with the application of high concentrations of heat and pressure. Thus, fried bacon adipose and others, after cooking, still retain their essential shape and residual high concentrations of lipids. Cooked meat may be chopped into pieces and maintained at temperatures well above the melting point of the lipid contained in its adipose tissue as is common in cooking many food dishes; but the adipose will not melt; and it is still a distinct substance.
It is known to those in the food trade and consumers alike that hamburger and sausage lose their appeal from the viewpoints of mouth feel and flavor when their adipose content drops below certain limits. The range of fat in hamburger varies from a low of about 16 percent to a high of over 30 percent. As a rule, the leaner the hamburger, the more expensive it becomes. Therefore, a typical quality of hamburger served in a restaurant contains only 74 percent lean meat and 26 percent fat.
One large fast food company specializing in hamburgers also uses a ratio of 74 percent lean meat/26 percent fat. In its "fancier" hamburgers, the fat content is decreased to 24 percent, still one-fourth of the product. According to consumer data gathered by the American Meat Institute, 1988 per capita ground beef sales were 28 7 pounds which equates to 7.054 billion pounds (population base of 245.8 million). This was approximately 39 percent of the total meat consumption (including processed meats).
Information provided by Texas A&M, released in 1988 and summarized in the following table, shows relative regional variations of lipids (fat) in hamburger (or ground beef).
TABLE ______________________________________ Region Regular* Lean* Extra Lean* ______________________________________ Northeast & 41% 37% 22% East Southeast 35 52 13 N. Central 21 38 41 S. Central 42 35 23 Mountain 68 23 9 West 37 37 26 Average 41 37 22 ______________________________________ *Regular = 75% Lean/25% Fat Lean = 80% Lean/20% Fat Extra Lean = 85% Lean/15% Fat
Ground beef constitutes 51 percent of all beef sold.
The importance of eating only sound, nutritious food has been recognized to a degree that today's consumer accepts the necessity of judicious food selectivity. This results in many consumers rejecting or limiting consumption of some foods heretofore considered to be healthful and delicious with culinarily less desirable but more healthful foods. This awareness has resulted in a revolution of individual eating habits that is crossing traditional international and cultural barriers in a wave of change.
In Western culture where both qualitative and quantitative adequacy of food exists, the public concern centers on such aspects as disproportionate intake of fats; overly refined, calorically concentrated foods; and, in particular, specifically currently undesirable components of some foods, such as those components containing significant amounts of saturated fats and cholesterol. As a consequence, traditional foods such as whole cream, eggs, cheeses, marbled meats, lunch meats, frankfurters, sausages, and the like have suffered diminution in consumption roughly in proportion to the concentration of cholesterol believed to be contained in them by the consuming public.
Such reduction in consumption has in some instances been profound as is the case with eggs, for example. A per capita reduction by half or more in consumption of eggs over the past decade has been seen.
Reductions in consumption of roasts, steaks, and other cuts of beef have also been substantial.
Hamburger and sausage adipose contains significant amount of cholesterol and is comprised of highly saturated fats. Both, according to current beliefs, are deleterious nutritional substances. The popular trend is avoidance or restriction of foods containing these materials.
It is clear from the foregoing and other examples that unsaturated fats and oils are preferred over more saturated ones and that cholesterol content constitutes the basis of a compelling consumer rejection of even traditionally highly prized foods with significant saturated fat contents.
A primary portion of a characteristic meat flavor is found in its native adipose tissue as was mentioned above. It is therefore no accident that the finest cuts of meats, containing as they do marbling and high adipose concentrations, have the most agreeable and desirable meat flavors as well as the highest saturated fat contents.
Cholesterol is also found primarily in the adipose portions of meat. It is possible, therefore, to reduce both the saturated fat and cholesterol in ground meat products such as hamburger and sausages by simply selecting the leanest cuts and closely trimming these cuts of any freely associated adipose tissue before grinding them. Unfortunately, the resulting hamburger or sausage is reduced in edibility. It tends to lose flavor, to be somewhat crumbly, and to be difficult to both chew and swallow. Also, the absence of adipose tissue in trimmed and ground, lean cuts leads to difficulties during preparation, such as tendencies for the meat to dry out as it cooks, to cook unevenly, and to stick to cooking surfaces.
The drying out of the meat as it cooks can make it unsuitable for commercial applications. In particular, in fast food establishments, it is important to prepare food in advance of high demand periods to prevent customers from waiting overly long for food. Such food preparation services have demonstrated great skill in developing strategies for dealing with this problem. Some have special fast cooking methods and even devices for preparing hamburgers rapidly which seal in juices so that the product does not become dry upon standing for short periods before consumption. And some go so far as to discard any prepared (cooked) hamburger meat if it is held for more than 8 to 12 minutes before purchase by a consumer to guarantee the quality of product which they sell.
Many methods for removing cholesterol from natural food products other than the above-discussed trimming of fat from lean cuts of meat are known.
Such methods usually require that the material which is to be treated to reduce its cholesterol level be either: in liquid form so that enzymes can be brought into adequate contact, or in dry form so that solvents can be applied for cholesterol removal.
Because of the foregoing limitations, no practical method for eliminating cholesterol and/or saturated fats from hamburger and other products containing comminuted meats has yet been discovered. The expedient of simply using lean meat is too great an expense for many institutions and consumers. Also, the consequent losses in flavor, texture, and moistness may make the end product unacceptable.
Those other proposed methods of reducing cholesterol relative to total weight of meat by simply adding moisture cause a loss of product identity since the characteristics of meats with high moisture content--notorious in the case of hams, for example--are significantly different from those to which water has not been added. Also, the shrinkage which results when an "added water" meat is cooked results in an eventual equal concentration of cholesterol on a weight-for-weight basis. Furthermore, the cost of the additional processing makes the "added water" meat more expensive than it would be if lean meat were simply purchased to start with.